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T O P I C R E V I E W

Robert Pearlman

Astronauts conducting second July spacewalk

On Tuesday (July 16), two ISS Expedition 36 flight engineers began a spacewalk at 6:57 a.m. CDT (1157 GMT), the second of two such excursions this month to prepare the International Space Station for a new Russian module and to complete additional installations on the station's backbone truss.

Chris Cassidy of NASA and Luca Parmitano of the European Space Agency and Italian Space Agency began the spacewalk when they switched their spacesuits to battery power.

finish the installation of bypass jumpers to provide power redundancy to critical station components;

route additional cables for a new Russian Multipurpose Laboratory Module targeted to arrive later this year;

replace a video camera on the Japanese Exposed Facility experiment platform;

relocate wireless television camera equipment;

troubleshoot a balky door cover over electronic relay boxes on the station's truss; and

reconfigure a thermal insulation over a failed electronics box that was removed from the station's truss last year.

Cassidy, who is designated EV1 for the spacewalk, is wearing a U.S. extravehicular mobility suit bearing red stripes. This spacewalk is the sixth of Cassidy's career. Parmitano, designated EV2, is wearing a spacesuit with no stripes and is making the second spacewalk of his career. He is the first Italian astronaut to walk in space.

Astronaut Shane Kimbrough at NASA's Mission Control Center in Houston provides ground support for the spacewalkers. Aboard the station, flight engineer Karen Nyberg is providing additional support during the extravehicular excursion.

A scheduled six-hour spacewalk outside the International Space Station was cut short on Tuesday (July 16) after water began leaking into the helmet of one of the two astronauts conducting the outing.

European Space Agency (ESA) astronaut Luca Parmitano was working on routing an ethernet data cable outside the orbiting outpost when he first reported feeling the back of his head was getting wet. Acknowledging that he had been sweating, Parmitano said that the amount of water he was feeling exceeded what he thought he could be perspiring.

"I don't understand where it's coming from," he radioed.

dabolton

Do they have a way to connect the suit in the airlock and drain it during repressurization? What is the nominal time to repressurize and open the suits?

Robert Pearlman

Presumably, they could drain the Liquid-Cooling and Ventilation Garment (LCVG), as it is filled from the payload water reservoir in the airlock, though whether that can be done during re-pressurization, I do not know.

That wouldn't have addressed the free-floating water inside Parmitano's helmet.

Today, they followed the a standard re-pressurization procedure for the airlock, with the exception that Parmitano's suit was kept on battery power. It took 11 minutes for the airlock to be re-pressurized.

Headshot

Slightly off-topic, but does anyone know if that astro-robot (robonaut?) onboard the ISS could be used for any of the tasks that were not completed today?

Robert Pearlman

Robonaut, in its current form, cannot go outside. A future version of Robonaut is envisioned to be used to assist spacewalkers, but that is at least a couple of years, if not more, away.

The other robot, Dextre, that rides at the end of the Canadarm2, is outside but is not capable of accomplishing any of the tasks slated for this spacewalk.

dabolton

Seems like they should line the helmets with a water-absorbant lining to at least lock in any errant moisture in the future. And/or add an external drain port to the helmet.

Hart Sastrowardoyo

Wouldn't an external drain port also drain any oxygen from the helmet as well?

Robert Pearlman

There is a purge valve on the helmet. After yesterday's press conference, I asked lead spacewalk officer Karina Eversley about why it wasn't used and she said that in this situation, it may have made matters worse.

The air flow in the helmet is such that were the valve used, it may have pulled the bulk of water from behind Parmitano's head up and over his face.

Robert Pearlman

NASA video release

Chris Cassidy Shows Off Faulty Spacesuit

Aboard the International Space Station (ISS), NASA astronaut Chris Cassidy discussed the ongoing efforts to solve a problem with Luca Parmitano's spacesuit during a downlink video July 30.

Cassidy demonstrated the suit and discussed some of the activities being done to troubleshoot the problem that caused water intrusion in Parmitano's helmet during a spacewalk conducted on July 16.

Robert Pearlman

Luca Parmitano has recounted his experience "drowning" in his spacesuit on his ESA blog:

As I move back along my route towards the airlock, I become more and more certain that the water is increasing. I feel it covering the sponge on my earphones and I wonder whether I'll lose audio contact. The water has also almost completely covered the front of my visor, sticking to it and obscuring my vision. I realise that to get over one of the antennae on my route I will have to move my body into a vertical position, also in order for my safety cable to rewind normally. At that moment, as I turn 'upside-down', two things happen: the Sun sets, and my ability to see – already compromised by the water – completely vanishes, making my eyes useless; but worse than that, the water covers my nose – a really awful sensation that I make worse by my vain attempts to move the water by shaking my head. By now, the upper part of the helmet is full of water and I can't even be sure that the next time I breathe I will fill my lungs with air and not liquid. To make matters worse, I realise that I can't even understand which direction I should head in to get back to the airlock. I can't see more than a few centimetres in front of me, not even enough to make out the handles we use to move around the Station.

I try to contact Chris and Shane: I listen as they talk to each other, but their voices are very faint now: I can hardly hear them and they can't hear me. I'm alone. I frantically think of a plan. It's vital that I get inside as quickly as possible. I know that if I stay where I am, Chris will come and get me, but how much time do I have? It's impossible to know. Then I remember my safety cable. Its cable recoil mechanism has a force of around 3lb that will 'pull' me towards the left. It's not much, but it's the best idea I have: to follow the cable to the airlock. I force myself to stay calm and, patiently locating the handles by touch, I start to move, all the while thinking about how to eliminate the water if it were to reach my mouth. The only idea I can think of is to open the safety valve by my left ear: if I create controlled depressurisation, I should manage to let out some of the water, at least until it freezes through sublimation, which would stop the flow. But making a 'hole' in my spacesuit really would be a last resort...